Congrats Noob, looks like you are doing a great job so far!
I find it useful to look at saving rates (percentages), not just absolute dollar values. It allows quick comparison to how you are doing compared to others. For example, it's commonly recommended in the USA for workers to save 10-15% for retirement. This is great if you want to retire in your 60's, but this isn't the typical MM reader. I believe MM and many here recommend a 50% or better savings rate (net, take home-after taxes).
I assume you are investing your $50K take home - $32K expenses = $18K into your Vanguard taxable account. Correct?? If this is true, than your gross savings rate is around 36% and your net (based on take-home) is around 56%. This is quite impressive! As a guideline, your need roughly 25 to 33 times your yearly expenses (4% and 3% guidelines, respectively) saved and invested to reach financial independence and have the opportunity to retire.
I'll focus on big picture risks. Others are better qualified to help optimize your expenses.
1) With a kids, I strongly recommend additional term life and disability insurance that is not tied to your job. What would happen if you couldn't work?? Would your family return to your home country or tough it out hear as a single mom with possibly 2 kids?
2) What's a realistic nearly-worse case with your support to parents in terms of our finances?
3) My biggest concern is lifestyle inflation with 1-2 kids. Are you budgeting for a bigger home or even a home purchase? If your wife is planning to w*rk for pay, have you budgeted for daycare or is it more cost-effective to have her stay a home until they are older? Have you budgeted for college savings? Of course, you have at least some control or even total control of all of these expenses. I strongly suggest that you form a rough plan/budget before having another child.
4) Where are you planning to retire? Back in your home country or here? If you'll return to your home country, is the cost of living much lower? What about your kids and grand kids, one day?
5) When are you planning to retire? If in your 60's (traditional) you'll probably be OK even if your savings rate slips somewhat. If you want out much sooner, I suggest some planning regarding the above. Ideally, I'd suggest learning to use a retirement planner like Firecalc or other free tools others can suggest. These are all just estimates, but the exercise encourages thinking things through!